Various types of agricultural implements have been developed that can be linked via an implement tongue member to a tractor hitch or other type of prime mover to facilitate different tasks including, for example, seeding, fertilizing and tilling. While there are many different factors that have to be considered when assessing the value of a particular implement, one relatively important factor is how quickly the implement can accomplish the task that the implement has been designed to facilitate. One way to increase task speed has been to increase implement width thereby reducing the number of passes required to perform the implement's task for an entire field. Thus, for instance, doubling the width of a seeding implement generally reduces the time required to completely seed a field by half.
With the development of modern high-powered tractors and implements, many implements extend to operating field widths of 40 feet or more. Hereinafter when an implement is extended into an operating configurations to accomplished specific tasks (e.g., seeding, tilling, etc.), the implement will be said to be in an operating position and have an operating width.
Unfortunately, while expansive implement operating widths are advantageous for quickly accomplishing tasks, such expansive widths cannot be tolerated during implement transport and storage. With respect to transport, egresses to many fields are simply not large enough to accommodate transport of a 40 plus foot implement into and out of the fields. In addition, often buildings and fences obstruct passageways and therefore will not allow transport. Moreover, many farm fields are separated by several miles and farmers have to use commercial roadways to transport their implements to and from fields. Essentially all commercial roadways are not designed to facilitate wide implement transport.
Recognizing the need for expansive implement operating widths and relatively narrow transport widths, the industry has developed some solutions that facilitate both transport and operating widths. To this end, one solution has been to provide piece-meal implements that can be disassembled into separate sections and stacked on a wheel supported implement section or on a separate trailer for transport. Obviously this solution is disadvantageous as it requires excessive labor to assemble and disassemble the implements between transport and intended use and may also require additional equipment (e.g., an additional trailer).
Another solution has been to provide a folding implement configuration. For instance, in a “scissors type” configuration, where an implement chassis is supported by wheels, right and left implement bars are pivotally mounted to the chassis where each bar is moveable between an operating position extending laterally from the chassis and a transport position where the bar is forwardly swingable over the tongue member and supportable by the tongue member during transport. As another instance, “pivotal-type” configurations provide a single implement bar centrally mounted for pivotal movement on a wheel supported chassis where the single bar is pivotable about the mount so that half of the bar extends over the tongue member and is supportable thereby and the other half of the bar extends away from the tractor behind the chassis. One exemplary pivotable configuration is described in U.S. Pat. No. 6,213,034 (hereinafter “the '034 patent) which issued on Apr. 10, 2001 and is entitled “Planter Apparatus and Method”.
In either of the scissors or pivotal configurations, the tongue member has to be long enough to accommodate half the implement bar length plus some clearance required to allow a tractor linked to the tongue member to turn left and right. Thus, for instance, where the implement operating width is 40 feet, the tongue member generally has to be greater than 20 feet long.
While task speed is one important criteria with which to judge implement value, one other important criteria is implement effectiveness and efficiency. In agricultural endeavors, perhaps the most important measure of effectiveness is yield per acre. For this reason, when seeding a field, a farmer wants to seed every possible square foot of the field and thereafter, when maintaining (i.e., tilling, fertilizing, etc.) and harvesting a field, the farmer wants to avoid destroying the plants in the field. To maximize field seeding, farmers typically travel along optimal field paths. For instance, to ensure that seed is planted along the entire edge of a field, a farmer typically starts seeding the field by first traveling around the edge of the field with a seeding implement at least once and often two or more times along adjacent consecutively smaller paths prior to traveling in parallel rows through the field. These field edge paths are generally referred to in the industry as headland passes. By performing one or more headland passes about a field edge prior to performing parallel passes, the farmer provides a space for turning the tractor and implement around between parallel passes while still covering the entire space along the field edge.
While headland passes increase overall field coverage, whenever a tractor is driven over field sections that have already been seeded, the tractor and implement wheels crush the seeds or growing plants that they pass over and therefore reduce overall field production (i.e., yield per acre). For this reason, as known in the industry, where possible, farmers routinely attempt to reduce the number of headland passes required in a field.
Unfortunately, the number of headland passes required to facilitate complete field coverage is related to the turning radius of a tractor and implement combination and the combination turning radius is directly related to the length of the tongue member between the implement and the tractor. Thus, for instance, where the tongue is six feet long the turning radius may require only one headland pass while a twenty foot long tongue may require two or more headland passes to facilitate complete coverage.
Recognizing that a short tongue during implement operation reduces the number of required headland passes and therefore increases efficiency and that a long tongue is desirable to accommodate pivotal and scissors type implement configurations, some industry members have developed staged tongue members that expand to accommodate implement transport and retract to provide a minimal turning radius during implement operation. One of these solutions provides a single stage telescoping tongue member including a first tongue member mounted to an implement chassis and a second tongue member that is telescopically received in the first tongue member. To facilitate expansion and retraction, a hydraulic cylinder is positioned within one of the first and second tongue members with a base member mounted to one of the tongue members and a rod secured to the other of the tongue members. With relatively large implements and tractors, the force required by the cylinder is relatively large. By placing the cylinder inside the tongue members, cylinder force is evenly distributed thereby reducing cylinder wear, reducing cylinder requirements and increasing the useful cylinder life cycle.
While better than non-telescoping tongue members, unfortunately, single stage members cannot telescope between optimal maximum and minimum lengths. For this reason, where single stage tongue members have been employed, either extended implement operating width has been minimized or extra headland passes have been used to accommodate a larger than optimum turning radius.
One other solution has been to provide a multi-stage tongue member that is able to telescope between optimal maximum and minimum lengths. Designing workable multi-stage tongue assemblies, however, has proven to be a difficult task. To this end, a separate cylinder is required for each stage in a multi-stage assembly. For instance, in a two stage assembly at least two cylinders are required. Unfortunately, in the case of a retracted multi-stage tongue assembly, the retracted assembly can only accommodate a single internally mounted cylinder (i.e., a cylinder mounted within the internal tongue assembly member). As indicated above, to balance cylinder load during operation and thereby minimize cylinder wear and increase useful cylinder lifecycle, the industry has opted to place tongue dedicated cylinders inside tongue member passageways and external tongue dedicated cylinders have not been considered a viable option.
One exemplary and seemingly workable multi-stage tongue assembly is described in U.S. Pat. No. 5,113,956 which is entitled “Forwardly Folding Tool Bar” and which issued on May 19, 1992 (hereinafter “the '956 patent”). The implement configuration in the '956 patent teaches a scissors-type implement having left and right bar members mounted to a wheel supported chassis for pivotal rotation between an extended operating position and a transport position over the tongue assembly. The tongue assembly is mounted to the chassis and extends toward a tractor including several (e.g., 5) telescoped tongue members including a distal tongue member 14 that actually links to a tractor hitch. To move the bar members between the operating and transport positions the '956 patent teaches that first and second hydraulic cylinders are mounted between the chassis and a point spaced from the chassis on each of the right and left bar members, respectively. By extending cylinder rods, the bar members are driven into extended operating positions and when the rods are retracted the bar members are driven into transport positions.
The '956 patent teaches that the tongue assembly can be extended and retracted while the bar members are driven between their operating and transport positions and by the first and second hydraulic cylinders by attaching braces between the bar members and the distal tongue member. More specifically, a first rigid brace is pivotally secured at one end about midway along the right bar member and so as to form an acute angle therewith and at an opposite end to the distal tongue member and a second rigid brace is pivotally secured at one end about midway along the left bar member so as to form an acute angle therewith and at an opposite end to the distal tongue member. The '956 patent teaches that when the cylinder rods are retracted so that the bar members are in the transport position, the tongue assembly is extended so that the distal end of the assembly clears the ends of the bar members. When the cylinder rods are extended, the bar members are driven toward their extended operating positions and the braces simultaneously pull the distal tongue member toward the chassis thereby causing the tongue assembly to retract. By reversing the rods so that the rods extend, the braces force the distal tongue member away from the chassis thereby causing the tongue assembly to extend. Thus, the '956 patent configuration replaces the tongue dedicated rods with the first and second braces on opposite sides of the tongue assembly, the braces in effect operating as rods to extend and retract the tongue assembly and providing a balanced load to the distal tongue member during extension or retraction.
The '956 solution, like other solutions, has several shortcomings. First, because the '956 patent configuration cylinders are linked between the chassis and the bar members, in the case of some implements, the cylinders will get in the way of implement components (e.g., seeding buckets, ground engaging tools, etc.). Similarly, because of the locations of the braces (i.e., secured between central points of the braces and the distal tongue member), the braces also will obstruct use of certain implement components.
Second, in order to simultaneously drive the bar members between the operating and transport positions and drive the distal tongue member between the retracted and extended positions, the cylinders have to be relatively large and therefore expensive. One way to reduce cylinder size is to modify the implement configuration to increase the acute angles that the braces form with each of the bar members when the bar members are in the extended operating positions. This solution, however, leads to a third problem with the '956 patent configuration. Specifically, to simultaneously provide a workable design including braces and accommodate larger acute angles that enable the use of smaller cylinders, the overall retracted tongue assembly length must be increased which is contrary to the primary purpose for which the assembly has been designed (i.e., to reduce tongue length during implement operation and increase tongue length during implement transportation).
In any extendable tongue assembly design, it is important to provide some mechanism to maintain the tongue assembly in the retracted position during implement operation and in the extended position during transport. In the case of configurations that rely on hydraulics to drive tongue members between extended and retracted positions, assuming the hydraulic system operates properly, the hose and cylinder pressures can generally be relied upon to maintain assembly positions. However, sometimes hydraulic systems fail and therefore, ideally, some backup locking system is provided.
Some assembly designs provide a manually operated mechanical locking mechanism to accomplish this task. For instance, to lock an assembly in an extended position, a farmer may be required to insert a locking pin through tongue member apertures that align when the assembly is retracted. Similar steps may also be used to lock the assembly in the extended position. Unfortunately, in the case of manual locking mechanisms, farmers may opt not to use the manual mechanisms and instead may simply rely upon the integrity of the hydraulic system.
Still other systems have been designed to include automatic locking mechanisms. For instance, referring again to the '956 patent, the '956 patent teaches a hydraulically operated latch locking mechanism that is mounted to the distal tongue member that engages a stop member that extends from the tongue member mounted to the chassis when the assembly is in the retracted position. When the assembly is in an extended position and the bar members are in a transport position, downward extending hooks at the distal ends of the bar members are positioned over receiving apertures such that, when implement support wheels are raised, if the hooks and apertures are properly aligned, the hooks are received in the apertures and lock the entire assembly, including the tongue members, in position for transport.
While better than a manual mechanism that may be ignored, the '956 patent locking mechanism still has shortcomings. For instance, the latching mechanism relies on gravity to maintain the latch over the stop member while the implement is in the operating position. Where an implement is pulled through a field and hits a bump or a pot hole, the latch member may be jostled upward overcoming gravity and thereby becoming unlatched. Similarly, during transport the implement may be jostled thereby causing the hooks to lift out of the receiving apertures so that the assembly becomes unlocked.
In addition, the hook and aperture transport locking mechanism may not always operate well as alignment of the hooks and apertures is required for successful operation and therefore manufacturing and operating tolerances have to be relatively tight. This is especially true where movement from the operating to the transport positions has to be performed in an uneven field environment where similar hydraulic forces may drive the left and right hand bar members to different relative positions with respect to receiving apertures (i.e., after movement toward the transport positions the bar member hooks on the left and right bar members may be differently aligned with receiving apertures on the distal tongue member so that some type of manual adjustment is necessary).
Moreover, the '956 patent requires separate mechanisms for locking the tongue assembly in each of the extended and retracted positions. As in the case of any apparatus, additional components typically translate into higher manufacturing and maintenance costs and therefore should be avoided whenever possible.
In addition to the problems described above, foldable apparatus have other shortcomings. For example, during pivoting or scissors type movement of implement bars to convert an assembly between transport and operating positions, the bars have to be supported in horizontal positions during conversion. One solution has been to provide a relatively robust pivot pin and corresponding components to provide the required support. This solution is disadvantageous as the costs associated with a reliable pivot pin and components of this type are relatively high.
Another solution for supporting implement bars during conversion has been to maintain wheels on the distal ends of the bars in ground engaging positions that support the distal ends there above. After conversion to the transport position, the ground engaging wheels are typically raised to upright positions where the wheels clear the ground below and the entire assembly is supported by a carrier frame and corresponding wheels. While this solution works relatively well when an assembly is positioned on a flat horizontal surface such as a road or a paved area, this solution does not work well under typical conversion circumstances. For instance, where conversion is attempted in an uneven field or in a field wrought with ruts, the force required to drive the ground engaging wheels over peaks and out of valleys is appreciable. Thus, while this solution is typically better than the unsupported solution, this solution generally requires relatively powerful motors and/or hydraulic systems to facilitate conversion. It should also be noted that this solution may prohibit conversion under certain circumstances where terrain blocks movement of the ground engaging wheels.
Yet another solution is described in the '034 patent. To this end, the '034 patent teaches that the pivot point is positioned adjacent a rear corner of a carrier frame with a nylon track runner forming an arc there around that extends between first and second track ends where the first end is at the other rear corner of the carrier frame. A mainframe is pivotally mounted at the pivot point to the carrier frame for rotation there around. A bottom portion of the mainframe rests on the track runner and slides there along during conversion.
By employing the '034 patent solution, advantageously, no components attached to the implement bar contact the ground there under and therefore ground engaging wheels do not impede conversion. Unfortunately, however, it has been found that even the '034 patent solution has shortcomings. Specifically, because the implement bar and attached components are often collectively heavy, the friction between the bottom portion of the mainframe and the track runner is often appreciable and therefore requires powerful and expensive hydraulics and/or motors.
Second, while manufacturing techniques are relatively good and therefore newly manufactured agricultural assemblies are well aligned and function properly, over the course of one or more seasons of use, many implements and components become misaligned or, in some cases, actually change their shape with wear. In the case of a pivotal-type implement, the implement bar and corresponding components have been known to become misaligned and even change shape (i.e., distal bar ends may droop over time). The '034 patent configuration does not provide means for compensating for misalignment or to compensate for implement bar shape deformation due to wear.
Therefore, a need exists for a system that enables easy conversion of a carrier frame mounted implement bar between transport and operating positions and to compensate for assembly component misalignment and deformed implement bar shape.